Resistance-grid.



H. W. CHENEY.

RESISTANCE GRID.

APPLIQATION FILED JUNE 24,1909.

Patented Jan. 4, 1910.

' UNITED STATES PATENT OFFICE.

HERBERT W. CHENEY, MILWAUKEE, WISCONSIN, ASSIG-NOR TO ALLIS-CHALMERS COMPANY, A CORPORATION OF NEW JERSEY.

1 full, clear, and exact Specification.

My invention relates to the construction of resistance grids for use 111 electric circuits.

In making and using resistance grids it isimportant to provide adequate means for reinforcing them, and this is particularly true in the case of grids of high resistance having frail structures.

It is the object of my invention to improve meansfor reinforcing or stiffening cast resistance grids and making it possible to. construct a grid of this type having a great length .of conductor /and a large amount of resistance in a small space, and one which will be supported so as to be mechanically rigid even should the grid in service be heated to a red heat.

Among other objects of my invention are to obtain strength, durability, compactness, and cheapness of construction.

Figure 1 is a view of one of the grids enibodying my invention, with parts broken away; Fig. 2 is an elevation of that shown in Fig. 1; and Fig. 3 is an enlarged sectional view taken along the line of Fig. 1.

Resistance grids havebeen made heavy and bulky in structure in order to withstand jars and-tendencies to warp out of shape when excessively heated. The resistance grids shown in these drawings are made light in structure. These grids are made of suitable resistance material in zig-zag form, for example substantially as shown in Fig. 1, so as to reduce into comparatively small space a resistance of considerable length.

The resistance grid consists of a conductor 10 formed substantially as shown and having its elements, such as 11 and 12, parallel and in integral contact to form a number of end-turns such as 13, the conductor terminating in enlarged ends 14 formed of hooks or holes open on one side. These hooked ends fit over insulated cross rods or bolts of a suspending frame. The number of grids may vary as desired. Projections 16 on the end-turns of the conductors provide forks shown in Fig. 3. the openings between Specification of Letters Patent.

Application filed June 24, 1909.

Patented J an. 4, 1910. Serial No. 503,996.

the projections 16 of the several end-turns from said conductor. The projections 16 are preferably integral with the grid. The rein forcing member is preferably made of some resilient sheet metal and bent to form a V in cross section. The insulationis obtained by means of a sheet of insulating material 18, such as asbestos, interposed between'the projections 16 and the reinforcing member. The asbestos is held securely to the slightly rough surfaces of the projections 16 by means of the spring action of the V-shaped reinforcing member 17; Because ofthis it is impossible for the insulating and reinforcing members to be dislodged by means of incidental jars or shocks. The same rein forcing or stiffening arrangement is used at opposite edges of the grid. By means of this reinforcing grids which are comparatively frail in structure are imechanically rigid avoiding contact of adjacent grids when jarred or heated and can be used .without having their elements warp to such an extent, when excessively heated, as to buckle up or come into contact with each other to form a shortcircuit.

There mayfbe many modifications of the precise arrangement here shown and described, and I. aim in my claims to cover the invention broadly.

hat I claim as new is:

1. A resistance grid comprising a cond uctor having forked end-turn portions, and a reinforcing member located in said forked portions and insulated from said conductor.

A resistance grid comprising a conductor having end-turns, said end-turns being each provided with a plurality of projections, and a reinforcing member located between said projections and insulated therefrom.

3. A resistance grid comprising a conductor having forked end-turn portions, and

a V-shaped.strip of metal located in said forked portion to reinforce said grid, said strip being insulated from said conductor. i. A Zig-zag resistance grid con'iprising a ciinductor having forked end-turn portions, and a resilient member located in and insulated from said forked portions to reinforce said grid.

5. In a resistance grid comprising a con- 6. ductor having forked end-turn portions, and

ductor having end-turns, said end-turns be ing provided with projections, and a resilient V-shaped strip of metal located between saidfprojections to reinforce said grid, said resilient member being insulated from said grid.

Av res1stance,.gr1d comprising a conmetallic member being insulated from each other.

8. A resistance grid comprising a conductor having end-turns, ro ections on said end-turns with openings etween said proectlons of said end-turns 1n alinement, and a reinforcing member located in the openings between said projections and insulated from the latter.

In testimony whereof I affix my signature, in the presence of two witnesses.

HERBERT W. CHENEY.

- l Vitnesses:

CHAs. L. BYRON, Ron. E. STOLL; 

